摘要:

AbstractThe action spectrum from 232 to 687 nm was determined for the transformation of protochlorophyllide into chlorophyllideain solutions of protochlorophyll holochrome Fran bean leaves. The whole ultraviolet region is effective. The peaks at 445 and 639 nm have a height ratio of 4.0. Only radiation absorbed in the protochlorophyllide itself is effective in transformation (absorption in aromatic amino acids of the protein and in carotenoids is ineffective).The activation spectra for fluorescence at 643 and 683 nm are measured for the holochrome before and after transformation, as well as the change in absorption spectrum that takes place upon transformation. By combining the various measurements the spectrum of inactive (non‐transformable) protochlorophyllide (peak at 440 nm) and the holochromatic chlorophyllideaare derived. In the latter spectrum the peaks at 419 and 435 nm are of about the same heigh

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07834.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Abstract2,2′‐Di(carboxymethylthio) pentan ‐4‐one was found to increase the stem height of intact tomato plants growing in pots under glass. Stem height was increased by 60 percent although this was accompanied by malformations in lamina development, leaf epinasty, and a final reduction in shoot weight. Stem growth of tobacco and potato were also stimulated by this compound but the deleterious effects on leaf development were less marked. Subsequent screening of chemical analogues, using as an assay the growth response of intact tomato plants revealed that 3,3′‐di(carboxymethylthio)heptan‐5‐one initially stimulated stem growth but then produced severe shoot damage, similar to that caused by phenoxyacetic acid herbicides. Both chemicals stimulated extension growth in a wheat coleoptile section test though to a lesser extent than indole‐3‐acetic acid.Like the carboxymethyl‐N:N‐dialkyldithiocarbamates, these straight chain compounds appear to possess true auxin activity that could be related to the formation of an incomplete un

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07835.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractPotato root tips were grown in cultures and the effect of blue, red, and white light on chlorophyll formation was studied. The roots grown in white light turned green in 4–6 weeks, whereas in blue or red light, green colour occasionally appeared at places. The chlorophyll contents, as determined by the spectrophotometeric method, were found to be maximum in unfiltered light followed by blue and red light. In white and blue light treatments chlorophyll a contents were higher than chlorophyll b, however in red light this was reversed. The results are compared with earlier experiments on chlorophyll formation in excised root

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07836.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effects of age on sodium fluxes in primary‐leaf sections from control and decapitated bean plants were determined. It was assumed that at high external salt concentrations the measurements represent mainly fluxes through the tonoplast, and that in brief efflux experiment subsequent to free‐space exchange efflux from the cytoplasma is essentially measured. Net‐ and influxes to the vacuoles increase during the period of leaf expansion and net chlorophyll synthesis. Both fluxes and amount of chlorophyll decrease rapidly in senescing leaves. The exchangeability of previously absorbed sodium also increased in senescing leaves. Decapitation delayed senescence and very much reduced the decreases in net flux and influx, and the exchangeability of sodium. The results are discussed in relation to solutes redistribution in the

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07837.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractDuring germination of the lucerne seed, proteolytic and gibberellinic activity increases. Exogenous GA added to the solution in which the seed was germinated caused an increment in proteolytic activity. CCC inhibited the biosynthesis of GA in the seed‐ ling, and had no effect on the proteases. This indicates that there are other factors Hum GA responsible for the increment in proteolytic activity duringMedicagogerminatio

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07838.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractTo clarify the mechanism of palmelloid formation by organic acids, the dissociation of the suspension of palmelloids in different media was studied. It was found that the palmelloids can be dissociated by the calcium ion at the low concentration of 6.8 × 10‐5M, but not by the magnesium ion. The dissociation is suppressed by the phosphate ion. Furthermore,Chlamydomonascells grown in media containing EDTA or GEDTA or in media deficient in calcium, are induced to form palmelloids. These results indicate that the effect of organic acids on the formation of palmelloids are due to their ability to chelate with calci

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07839.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractUsing hydrocultured pea plants, 109 bacterial strains (42 from shoots) were isolated from shoots, roots, and from the hydroculture medium. 58 different strains (26 from shoots) were able to produce IAA from tryptophan, 15 different strains (7 from shoots) were able lo destroy IAA. (Included are 13 strains possessing both properties.) As far as they could be identified, the IAA‐producing and ‐destroying strains belong toPseudomonas(by far dominating),Achromobacter, Alcaligenses, Bacillus, and Flavobacterium.The IAA‐destroying activity strongly depends on the physiological state of the bacteria and the milieu conditions. Bacterial IAA production (but not IAA‐degradation) is supposed to be important for th

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07840.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractUsing IAAC14, polar transport has been studied inHelianthus annuusshoots in which stem elongation was inhibited by a transverse gravity stimulus induced by horizontal orientation of the plant with daily rotation. Marked inhibition of polar transport of IAAC14occurred in the treated plants. A similar degree of inhibition occurred in the upper and lower halves of non‐rotated horizontally trained shoots. Horizontal orientation of stem segments during the transport test had no consistent effect upon IAA transport.Pretreatment of erect plants with gibberellin greatly enhanced IAAC14transport and also reduced the inhibitory effect of horizontal orientation. Pretreatment of erect plants with non‐radioactive IAA or ethylene inhibited transport of IAAC14and induced the same symptoms in the shoot as the transverse gravity stimulus.The similarities between the response of the auxin transport system to gravity stimulation, IAA and ethylene are discus

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07841.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe activity of α‐analyses in various plant organs was examined and the relation‐ ship between the enzyme activity and the leaf sheath elongation of dwarf mutants of maize was investigated.It has been shown that α‐amylase exists in various plant organs. Especially high activity was detected in the bean hypocotyl. The regional activity of a‐amylase in the epicotyl of the pea and the hypocotyl of the morning glory was examined. Higher activity was observed in the regions closer to the cotyledons. In the first leaf sheath of d5mutants of maize, GA3‐treatment resulted in the promotion of α‐amylase activity, and there was a parallelism between GA3‐induced elongation and α‐amylase activity. Removal of the endosperm from seedlings did not influence the GA3‐indnced elongation of the leaf sheath or the promotion of α‐amylase activity. From these results it is concluded that at least some of the α‐amylase is actually formed in the leaf sheath, and that there exists a distinct parallelism between the GA3‐induced promotion of enzyme activi

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07842.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

AbstractThe effect of oxygen concentration on the rate of CO2‐uptake in continuous and intermittent light was studied as well as the CO2‐fixation during a short dark period after light was turned off. In addition the dark respiration and the CO2‐compensation point of attached and detached corn leaves were determined. Leaves of 4 to 22‐day old plants were used as experimental material. A closed circuit system of an infrared carbon dioxide analyzer was employed to measure the rate of CO2‐exchange. It was found that in an atmosphere consisting of 100 % oxygen, there was about 50 per cent inhibition of the rate of CO2‐uptake in continuous and intermittent light compared to that in an atmosphere consisting of 21% oxygen. The same was true of the rate of CO2‐fixation in darkness during a short period after the light was turned off. Since the response to oxygen concentration of the CO2‐uptake in light and of the CO2‐fixation in darkness after the light was turned off were similar, it is concluded that the fixation of CO2in the short dark period represents an over‐ shoot of photosynthesis. The rate of dark respiration was little affected by the oxygen concentration in the ranges used in the experiments. The carbon dioxide compensation point which has been observed in leaves of 4 to 14‐day old plants was not influenced by either oxygen concentration or light intensity. Since the changes in the rate of CO2‐uptake due to changes in the concentration of oxygen and light intensity had no effect on the CO2‐compensation point, it is concluded that a reabsorption of respiratory CO2by photosynthesis could not account for the low value of this point. These results are interpreted as a further corroboration of the statement that the leaves of corn lack the process of photorespiration and that dark respiration is inhibited in light.It was observed that the rate of the CO2‐uptake gradually increased in plants which were from 4 to 22‐days old. The inhibitory effect of high concentration of oxygen on the rate of CO2‐uptake was relatively higher i

ISSN:0031-9317    

DOI:10.1111/j.1399-3054.1969.tb07843.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY